This is a Mentored Scientist Development Award application to develop and evaluate statistical methods for characterizing developmental courses of alcohol use in late adolescence and young adulthood and also to identify critical background and dynamic risk factors and comorbid conditions associated with heavy drinking. The training goals, which will be met through an active mentored research plan as well as formal coursework, seminars, self-directed readings, and workshops, are threefold: (1) to increase knowledge in the area of alcohol studies from the perspectives of descriptive and experimental psychopathology, (2) to acquire advanced skills in longitudinal methodology with an emphasis on developing proficiency in the foundations of basic statistics, and (3) to receive training in the collection, management, and analysis of daily process studies, including interval-, signal-, and event-contingent sampling. The aim of the proposed research project is to characterize developmental courses of alcohol use and to examine fixed and time-varying risk factors that are associated with membership in maladaptive drinking trajectories. Although newly emergent methodology is available to identify developmental courses and to examine the influence of risk factors on these courses, extant research in the field rarely exploits this methodology. Data from three multi-wave (at least 5 waves) panel datasets assessing drinking in adolescents and young adults will be used to systematically explore and refine these methodological tools. In addition, although analysis of prospective panel data is useful for demonstrating general tendencies and causal associations over long intervals, their nature precludes fine-grained analysis of drinking patterns and can obscure variation in individual patterns and the nature of short-term, unidirectional and reciprocal influence processes. Thus, daily process methods, which serve as a paradigm for studying psychological processes by examining ongoing experience in everyday life, also will be used. One of the planned studies will utilize daily interval sampling to assess drinking, smoking, mood, and stress levels in a sample of 100 college students over a ten-week period. Future work will include signal- and event-contingent sampling, which improves the temporal resolution of models studying bivariate and multivariate relations. The daily process study will have a particular emphasis on understanding the mechanisms that underlie alcohol-tobacco comorbidity. These investigations will yield substantive contributions related to the etiology and course of pathological drinking, methodological contributions in the area of longitudinal data analysis, and "translational" contributions disseminating these methodological developments to researchers in the alcohol field.